Possible Clues:

• Piano out of tune, right? Could be better
• Football player, sometimes
• Fourth-down player, often
• A colloquial better or a regular client
• Professional gambler; client (inf.)
• Informally, a customer or someone who bets
• Better - rugby player - river boatman
• One betting; 4's prey (slang)
• Better boater
• Gambler; customer